Yeah, figures. I asked them the week prior when setting up my appointment what gear they run the car in on the dyno and told them for this vehicle that I heard on the forums it's fifth gear.

They said they run it in whatever gear is closest to 1:1. I assumed they were going to look it up and use the correct one. When I showed up yesterday, I forgot to ask again, and just remembered to ask after all the dyno runs were complete after I already left.

I appreciate the link. I emailed the shop the information so that they would have it for the next M5 owner, and can see it wasnt just "something I heard".

Yeah, figures. I asked them the week prior when setting up my appointment what gear they run the car in on the dyno and told them for this vehicle that I heard on the forums it's fifth gear.

They said they run it in whatever gear is closest to 1:1. I assumed they were going to look it up and use the correct one. When I showed up yesterday, I forgot to ask again, and just remembered to ask after all the dyno runs were complete after I already left.

I appreciate the link. I emailed the shop the information so that they would have it for the next M5 owner, and can see it wasnt just "something I heard".

Goodspeed said it doesnt matter on the Maha Dyno: "When we run in crank mode on the MaHa gear doesn’t matter. Fifth gear on the M5 is simply overkill as speeds would get out of hand quickly. That’s why we choose to do them in 4th gear!"

They are saying their dyno is an extremely accurate dyno. A $250,000 dyno that is of the same type BMW itself uses. That the car on 91 would be around 525 HP ( 550 HP on 93 as BMW rated), and with mods my mods on 91, I'm at 556. Hence an approximate 30HP improvement. Thus the results are just as expected.

They've mentioned other subaru's make 420 elsewhere and put 360 down here.

Anyway, that's the story. Obviously with no stock runs, there is no exact measurement of mod increases.

They are saying their dyno is an extremely accurate dyno. A $250,000 dyno that is of the same type BMW itself uses. That the car on 91 would be around 525 HP ( 550 HP on 93 as BMW rated), and with mods my mods on 91, I'm at 556. Hence an approximate 30HP improvement. Thus the results are just as expected.

They've mentioned other subaru's make 420 elsewhere and put 360 down here.

Anyway, that's the story. Obviously with no stock runs, there is no exact measurement of mod increases.

Thanks for sharing. But without a before, claiming 30HP gain from intakes is just not fair to others shopping for intakes. That's a random guess.

I recall the Gruppe M CSL carbon intake for the E46 M3 losing power on the dyno, so the jury is out on them.

I never stated a 30WHP gain from "intakes". Hopefully anyone shopping for an intake system would read this post and title in its entirety.

I stated that theoretically, the full catback RPI GTS Exhaust system coupled with the Gruppe M intake could produce approximately 30WHP (and showed the reasoning behind that assumption). I also clearly stated that without before dyno's that this was just speculation.

Furthermore, reading information about the E46 M3 intake has absolutely nothing to do with this car or intake design and is irrelevant.

Studie Japan (a thrid party) did an actual before and after run and showed results of an increase to the wheel. Granted, they were working with Gruppe M, so it could be bias. However, IND did before and after dyno runs with the M5 Gruppe M intake and showed actual wheel horespower increase as well. So someone shopping for an intake would look at that data before purchasing.

Someone wanting to know what their Gruppe M intake and RPI Exhaust M5 would put down on a Maha dyno would look at this thread.

The bad thing amongst all these internet dyno horsepower wars is that people dont do enough research. Back in the day turbo imports became dyno queens and Euro cars wanting to follow that trend started using wrong dynoes (Dynojets) in order to make a fake impression of a higher hp gain. Back then most Euro cars were naturally aspirated and for the part companies it made sense to test their product on dynojets. The true wheel hp that is being put down to the black is displayed by dynoes like Maha or Mustang dyno. The OP's numbers are most likely as close to reality as it will get.